Flywheel/Starter Ring Gear

The 4A, 4AB, 4AC, 4AD cars, including the SM 1500 Roadster and SMX
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Mark Thompson
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Flywheel/Starter Ring Gear

Post by Mark Thompson »

I am working on my second Singer 4AD restoration. I have some questions regarding the mounting of the starter ring gear on the flywheel.

When I disassembled my clutch and bell housing, I noticed that a number of modifications had been made to the assembly. The bottom of the bell housing had a chunk deliberately removed (line-drilled & broken out) at the bottom. The throwout bearing fork had been cut off and a different fork brazed onto it. The throwout bearing was different but workable. Also, the flywheel had four allen head set screws installed up against the starter ring gear. The ring gear was badly chewed up in several places.

Being somewhat of a purist, I decided to start over. I was able to obtain a used bell housing, throwout bearing fork, and flywheel from Paul Barber in GA. When I compared the two flywheels, I observed a major difference. The original flywheel had the chamfer on the engine side of the flywheel. The one I received from Paul had the chamfer on the clutch side of the flywheel. I assume that the one from Paul is right, since the starter thrust gear engages from the clutch side. I also assume that the original flywheel starter ring was reversed to use the side of the starter ring that wasn't chewed up. I had only started the engine twice before I disassembled it. I hadn't noticed any strange noises when I started it and the starter gear doesn' appear to be damaged.

My first question: Is reversing the starter ring gear a workable, satisfactory solution for a worn ring gear? Is the chamfer not important?
Does anyone have expereince with this? My repair manual doesn't address this. The repair manual does raise another question. It says that you should only heat the starter ring gear in an oven prior to installing it on the flywheel. It cautions against using an open flame or torch. My local clutch expert that rebuilds my clutches and pressure plates assures me that he uses a torch to install the ring gears all the time. Is the manual correct or overcautious?

I plan to use the flywheel that Paul provided, however, I ordered a starter ring gear from Trevor Cornelius and plan to rebuild the original flywheel to keep for a spare. Any advice would be greatly appreciated.
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mikeyr
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Post by mikeyr »

I have reversed the ring gear with no problems, don't remember the chamfer answer for you. I stuck the flywheel in the freezer and my wife and I heated the gear with 2 torches. One trick is to make sure the ring gear is heated as evenly as possible or it could crack or warp when it hits that frozen flywheel.

This was 15 years ago on my 4AD and have never had any problems.
Mike Rambour. Site Administrator
1953 Singer 4ADT (sold), 1934 Singer 9 Le Mans, 1934 Singer 1 1/2 4-Seater Sports (sold), 2009 BMW K1300GT
BRG
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Flywheel/Ring Gear

Post by BRG »

Mark,

The chamfer you are talking about is a relief for the starter motor gear to engage the ring gear easier. It should work okay reversed. As for heating the ring gear, Mike is right about the torch. Even heating and I have Never put a flywheel in the freezer(not that I am afraid of my wife!) but the heat transfer to the flywheel is negigable and you can see the ring gear slip on the wheel and not overheat the gear. Some light tapping to set the gear is acceptable.
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fly4ad
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Re: Flywheel/Starter Ring Gear

Post by fly4ad »

I finally obtained a hoist and engine stand to pull the engine and trans from the near bare frame of the 1952 4AD I’m restoring. Once I separated the transmission from the engine, the first thing I noticed was that about half of all the gear teeth are ground off the flywheel. With that said, what options do I have? From what I gather regarding the above posts, it sound like the gear can be replaced. Mine appears to be all one piece?
Thanks for the help!
Fred
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Re: Flywheel/Starter Ring Gear

Post by BRG »

I have seen some on the UK Ebay site but they show up sporadically.

BRG
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fly4ad
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Re: Flywheel/Starter Ring Gear

Post by fly4ad »

OK, after a closer look, the ring gear is replaceable. Are these gears available?

BRG, were you refering to the complete flywheel or just the gear?

Thanks,
Fred
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Re: Flywheel/Starter Ring Gear

Post by BRG »

Fred,

Just the gear.

BRG
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